Draft device for furnaces



M. M. GRANT.

DRAFT DEVICE FOR FURNACES.

APPLICATION mm mm. 9. 191a.

Patentd Aug. 5, 1919.

ivrrinvinnn ivn GRANT, or ALLIANCE, OHIO.

DRAFT DEVICE FOR FURNACES.

Specification of Letters Patent.

Patented Aug. 5, 1919.

AppIication filed March 9, 1918. Serial No. 221,438;

To all whom it may concern j Be it known that I, MELVILLE M. GRANT, a citizen of the United States, residing at Alliance, in the county of Stark and State of Ohio, have invented certain newand useful Improvements in Draft Devices for Furnaces, of which the following is a speoification.

This invention relates to new and useful improvements in draft devices for furnaces, and the primary object of the invention is to provide a new and improved means for injecting air into the furnace, in a heated condition, whereby the same mixes with the gases therein to minimize the amount of smoke produced as well as economizing in the expenditure of fuel by. causing a more perfect combustion, and a greater resultant heat. i

Another object of the invention is to provide a device of this character for the purpose specified, which comprises an attachment adapted to be applied to a furnace door which comprises means for admitting air to the furnace and heating said'air before it intermingles with the heated gases within the furnace, thereby obviating any likelihood of cracking the boiler plates by a premature injection of cold air onto the same. i

Still another object of the invention is to provide a device of this character which is easily and simply constructed, inexpensive to manufacture, and one which will be very efficient in operation.

With these and numerous other objects in view, my invention consists of the novel fea tures of construction, combination and arrangement of parts which will be herein referred to and more particularly pointed out:

in the specification and claims.

In the accompanying drawings:

Figure 1 is a horizontal section through the device,

Fig. 2 is a rear elevation thereof,

Fig. 3 is a longitudinal section showing a slight modified construction, and

Fig. 4 is a similar view showing a further modified form.

In describing my invention, I shall refer to the drawings in which similar reference characters designate corresponding parts throughout the several views. Althou 11 several modified'forms are illustrated, t e principle is the same throughout the various modifications. The description of the same will be taken up in detail.

In Figs. 1 and 2 of the drawings, I have illustrated one form of my invention, which 1s adapted to be applied to a furnace door, the numeral 1 designating the door which is provided with a substantially centrally disposed air inlet opening 2 therein. Adjacent edges of the opening 2 are provided with an mwardly projecting lip 3 for apurpose to be hereinafter more fully described. The outer edges of the lip 3 are slightly flared, as is clearly shown in Fig. 1 of the drawings. Positioned adjacent the inner sideof the door and alining with the opening 2 in said door, is an air baflie plate 4. The plate a is considerably larger than the opening 2 and projects beyond the edges thereof. The edges of the plate i are provided with in wardly extending arcuate flanges 6, which extend to a point adjacent but spaced from the lip 3 of the opening 2. These curved flanges 6 are adapted for cooperation with a casing 7 that is connected with said door, the casing extending inwardly and being connected with the door to form air ducts owing to their formation which are tortuous toimpart a whirling motion to the air when the same passes therethrough. These air ducts are preferably divided by partitionsil that extend between the casing and flange as is clearly shown in Fig. 2 of the drawing. The inner face of the baffle plate 4: is preferably provided with a plurality of projecting lugs 10 which form heat radiating membersadapted to heat the air when the same strikes the baffle plate before it enters the furnace through the air ducts around the edge of said plate.

InFig. 3 of the drawing, I have shown a l slightly modified form of this invention,

wherein the baffle plate designated by the numeral 11 is concave, and is positioned adjacent the air inlet 2 of the door 1. A casing 12 is secured to the inner face of the door and projects along the curved edges of the plate 11 to form an air passage 13 preferably divided into a plurality of ducts 14 by partitions positioned therein as is clearly shown in Fig. 3 of the drawings. The prin ciple in this modification is the same as the one before described, and the only difference is a different construction of the baffle plate.

still further modified form of this invention, wherein the baffle plate designatedby the numeral 16 is provided with an inwardly projecting flange 17 similar to the flange 6 in the first described form, but in this device, the casing designated by the numeral 1 8 isslightly enlarged, and a more pronounced chamber is formed within the door for heating the air before the same is ejected into the furnace. The air ducts of this form of the device are of a slightly diflerent form from the air'ducts before described. The plate is supported"- by the usual securing means or bolts 19, but said plate is bowed as shown at 20-at its center point, and is provided with a :plurality of perforations 21 therein that formsupplemental air inlet means. i

I From the foregoing description, the operation-of this devlce is obvious. Although I have shown the device 'as applied to a furnaceidoor, it is obvious that they may be ap pliedto anypartgof the furnace wall thatis provided with an air inlet opening. The air, when it enters through the opening strikes the baflie plate, and is retarded within the chamber, formed between said plate and the door or. wall of vthe furnace suflicient time to heatithe airsothat cold air will not be in jected intothe furnace which would be likely to erackr the boiler-plate. After the air has been heated the same is carried by suction aroundtheedgesof the baffle plate through the airduetsand into the furnace. This inj ection of heated air will greatly reduce the amount-otsmoke produced, and also economize in fuel. The air mixes with the gases andisburned whereby a maximum amount of heat, is produced at a minimum expenditure of 'fuel. I

From the foregoing description taken in connection with the accompanying drawing, it is thought that a clear and comprehensive understanding of the construction, operation andadvantages of my invention may be had, and while I have shown anddescribed the device as embodying a specific structure, I. desire that it be understood that such changes may be made in said structure asdo not depart from the spirit and scope of the invention as claimed.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is:

1. A draft device for furnaces including a casing provided at one side with an air outlet port and in the opposite side with a circular series of air inlet ports, a heat radiating plate carried by the casing located centrally of the circular series of ports, and an annular air conducting flange surrounding the outlet port and flared inwardly toward the inner surface of the radiating plate whereby to draw heated air from the entire area of the plate.

2. A draft device for furnaces including a casing provided in one side with an air outlet port and in the opposite side with a circular series of air inlet ports, a heat radiating plate arranged centrally within the circular series of inlet ports, heat radiating lugs carried by theinner surface of the plate, an annular air conducting flange surrounding the outlet port extending and flared toward the lugged surface of the heat radiating plate whereby to draw air from the entire area of said plate.

3. A draft device including a casing attachable to a furnace provided at one side with a centrally disposed outlet port and at the opposite side with a circular series of inlet ports arranged concentric with the outlet port, a heat radiating plate arranged centrally of the circular series of inlet ports,

heat radiating lugs formed on the inner surface of said plate, a circular flange surrounding the outlet port extending and flared toward the heat radiating plate whereby to draw heated air from the entire area of the plate, and a curved flange carried by the plate and arranged to direct the air flowing through the inlet port outwardly of the circular flange.

In testimony whereof, I aflix my signature hereto.

MELVILLE M. GRANT.

Gopieaof th leipatent may he obtained for fivecents each, by addressing the Commissioner of Patents,

Washington, D. G. 

